The present invention relates generally to a phosphate cement composition, and more particularly to a sprayable and pumpable phosphate cement composition that cures rapidly, and is flame and heat resistant.
Portland cement has traditionally been the cement of choice. It is typically a mixture of water, calcined lime and silica. It is cheap to produce, easy to handle. There are, however, several disadvantages to Portland cement. Source materials often have inconsistent quality. Portland cement is often highly viscous which is acceptable for pouring and spreading, but is a major disadvantage if pumping or spraying is desired. Portland cement also has a slow cure rate.
An alternative to Portland cement is phosphate cement. Phosphate cement typically comprises an acid component such as phosphoric acid or an alkaline earth phosphate salt (e.g., magnesium phosphate), and a base component such as magnesium oxide. Phosphate cements tend to cure rapidly, and have excellent chemical stability and compressive strength. Due to the rapid cure characteristic, phosphate cements are, however considered undesirable for spraying and pumping.